UPDATE 2013 - There is now an actual Spam Filter as well as Inbox and Other.
Click through on Other and then you will see next to Inbox and Other a More option with a drop down menu - that's where the spam filter is.
I am indebted to Matt Garrett for alerting me to the fact that Facebook has a spam filter for its private message system.
On my home page, I looked at the left hand sidebar and clicked the Messages tab. Another menu dropped down with an option called 'Other'.
Inside were 52 messages stretching back over six months. Sure, some of them were about events that I would not particularly have wanted to know about, but there were three or four messages from people that I do like to talk to and from whom I have not heard since.
How rude must they think me?
So be aware and, just as you do with your email spam filter, check the 'Other' inbox regularly to ensure that no one important has been consigned to that dead zone.
If you find a message that you do want to read, click on it and a new drop down menu will appear at the top headed 'Actions'. From this you can check the box to Move it to the Messages Folder.
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